I have one of these and I’m wondering how to connect up a battery. With the pico you can connect to VSYS and ground and you’re good to go, but I’m not sure if/where this routes to on this.
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I found the schematic here https://www.waveshare.com/w/upload/4/4c/RP2040_Zero.pdf
It looks like the 5V pin is VSYS, does that look right?
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Hi Doug,
Just did a little test here in-house and checked the pinouts and it appears that you can power the RP2040 directly over the 3.3V line as it appears to be connected to the RP2040 IOVDD on the board. You’ll just want to make sure that your voltage doesn’t spike above 3.3V as typically the voltage range for RP2040’s is 2.5~3.3V although it can drop as low as 1.8V no problem (although I wouldn’t recommend this as other issues begin to occur at low voltage).
If you’re connecting it to a battery or batteries, I would suggest including a buck converter and a small decoupling capacitor to ensure that you’re getting relatively noise-free power supplied to your board at the appropriate voltage.
p.s. the RS2040 seems to draw only a few milliamps when idling on this board.
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Thanks, that’s great. I’ll see how I go 
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The RPi Pico has :-
VBUS (USB 5V).
VSYS input to 3V3 regulator, (1.8V to 5.5V) this would be a LiPo battery connection.
3V3 output of regulator.
Diode separation of VBUS & VSYS on board.
The 5V on the Board linked above would be connected to the USB 5V.
This connects to the ME621 LDO regulator to produce 3V3.
From the datasheet the input range for the regulator is 4.3V to 6.5V.
Battery connection to this board is not straight forward as the RPi Pico.
Regards
Jim
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Hi Doug,
Neat lil board, you could also get away with far less circuitry from a look at the schema (I’m not too sure if the ME621, the one that I have seems to be - ref the photo below, though in the schematic RT9013-33 is listed as the regulator)
Both LDO’s will happily output a pretty stable voltage all the way down to 3.3V from Vin max if you are using a LiPo.
Hard agree on the Vmax spec, for both LDR’s though as the voltage falls past what it has been designed to output it will close to linearly fall off
From there all that is required is a diode from between the battery to Vsys so that the battery doesn’t explode and seamless switchover from USB-Battery can occur.
Other interesting resources:
Powering from above 12V: WiFi Garage Door Controller with Raspberry Pi Pico W - Tutorial Australia
Another more complex example of switching to battery power, the P-FET will have a lower voltage drop => less power lost CE-PiicoDev-LiPo-Expansion-Board-for-Raspberry-Pi-Pico/schematic.pdf at main · CoreElectronics/CE-PiicoDev-LiPo-Expansion-Board-for-Raspberry-Pi-Pico · GitHub
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Sorry I am bit confused, Is it possible and safe to power this board waveshare RP2040-Zero from the 5v line, using 5v input? I have one of these boards and a hoping to use it with a battery / solar panel i also already have a 5v step down voltage regulator. I am a bit of a noob to all this, so any help to understand is very much appreciated.
cheers
Tested this board.
Powered via the USB-C connector, RGB Led flashed three colours.
Disconnected the USB-C connector and connected a 5V power supply to 5V & GND, RGB Led flashed.
So the answer would be Yes it is ok.
But, DO NOT connect both USB-C and separate power supply at the same time.
As @Liam120347 mentioned you need a diode to ensure one supply does not overload the other.
Also make sure it is +5V and the right polarity when you connect a separate supply or the board may die.
BTW the 3.3V is an output, you cannot power it via this pin.
Regards
Jim
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